Pharmaceutical composition useful for the treatment of cardiovascular diseases

ABSTRACT

A pharmaceutical composition is described comprising ibopamine and an ACE-inhibitor. Such composition is useful in the treatment of cardiovascular diseases, more particularly of hypertension and heart insufficiency even when the latter is associated with or caused by hypertension.

This invention relates to a composition comprising ibopamine and anACE-inhibitor.

Ibopamine (diisobutyril ester of epinine) is a drug useful incardiovascular therapy and has been described in U.S. Pat. Nos.4,218,470 and 4,302,471. Ibopamine has a complex pharmacological effectbased on the stimulation of dopaminergic, alpha-adrenergic andbeta-adrenergic receptors. In particular, ibopamine does not modify theblood pressure and the heart rate either in normal subjects or inpatients suffering from heart and renal insufficiency, but it showsadvantageous effects in heart insufficiency therapy due to its abilityof increasing heart delivery and blood flow towards organs and muscles,thus improving perfusion of vital organs, such as the heart, kidney,brain, and skeletal muscles.

Ibopamine may be administered helpfully over a long period by mouth.

While (in the therapy of heart insufficiency associated with or causedby hypertension) ibopamine was not used due to potential effects onalpha-adrenergic receptors and possible hypertensive effects, it hasrecently been discovered that ibopamine is capable of inducing amoderate and gradual drop in blood pressure in hypertensive patientswithout affecting blood pressure when the latter is normal, both inhealthy subjects and in cardiovascular and renal pathologies, asmentioned above, and indeed it can heap in restoring blood pressure inpatients suffering from renal insufficiency which are subjected todialysis with consequent hypovolemia and drop in blood pressure.

ACE-inhibitors, that is, the Angiotensin Converting Enzyme inhibitors,are widely used as antihypertensive drugs.

In some patients, however, ACE-inhibitors cause drops in blood pressureand impairment of the renal function with an increase of azotemia and ofplasma creatinine. Specific examples of ACE-inhibitors are:

captopril (Merck Index, 10th Edition, No. 1747, page 244)

enalapril (Merck Index, 10th Edition, no. A-5, APP.1)

ramipril (HOE-498) (Annual Drug Data Report 6, 137 (1984))

quinepril (Annual Drug Data Report 5, 41 (1983))

trandolapril (Annual Drug Data Report 7, 768 (1985))

zofenopril (Annual Drug Data Report 6, 162 (1984))

pivopril (Annual Drug Data Report 8, 146 (1986))

cilazaprilat (Annual Drug Data Report 8, 32 (1986))

phenacein (Annual Drug Data Report 7, 20 (1985))

perindopril (S-9490) (Annual Drug Data Report 7, 99 (1985))

pentopril (CGS-13945) (Annual Drug Data Report 5, 40 (1983))

delapril (CV-3317) (Annual Drug Data Report 6, 12 (1984))

cilazapril (Annual Drug Data Report 7, 579 (1985))

ancovenin (Annual Drug Data Report 6, 20 (1984))

lisinopril (MK-521) (Annual Drug Data Report 5, 124 (1983))

alacepril (Japanese Patent Application No. 78/82809)

fosenopril (U.S. Pat. No. 4,656,188)

nicotianamin (East Germany Patent DD 226 880).

Now, it has been unexpectedly found that the combined administration ofibopamine together with an ACE-inhibitor is helpful in the therapy ofcardiovascular diseases, as ibopamine overcomes the drawbacks and theside effects of ACE-inhibitors not only in heart insufficiency, but alsoin hypertension therapy, where ACE-inhibitors are widely used, whereasibopamine was not used previously.

It has also been found that the blood pressure drop induced by ibopaminein hypertensive patients may be further enhanced, with no drawbacks andwith no side effects, by the combined use of ibopamine and anACE-inhibitor.

Therefore, it is one object of the present invention to provide apharmaceutical composition which is useful in the therapy ofcardiovascular diseases and comprises ibopamine and an ACE-inhibitor.

In particular, said pharmaceutical composition is useful in thetreatment of hypertension, heart insufficiency and heart insufficiencyassociated with hypertension, as the combination of ibopamine with anACE-inhibitor reduces or removes the negative effects of ACE-inhibitors.Said composition is therefore a particularly suitable and innovativemeans for the treatment of heart insufficiency having different etiology(dilatative, ischemic, alcoholic) even when the latter is associatedwith hypertension, as well as for the treatment of the hypertensionetiology.

The advantages of the combined therapy have been revealed by animprovement of the heart functionality with low or moderate doses ofACE-inhibitors; marked increases in heart delivery have been observedand, in prolonged treatment, also symptomatic and functionalimprovements of patients without a drop in pressure below the valuescompatible with their circulatory conditions, in particular as regardsthe systolic pressure. This has proved particularly advantageous inolder patients with limited renal functionality and limited heart andbrain irrigation. In particular, in addition to the lack of pressuredrops, deterioration of the renal function with increase of azotemia andof the level of plasma creatinine have proved absent.

In a certain number of patients the side effects of this type limit thetherapeutic use of ACE-inhibitors, or allow their administration only atreduced doses, which are not in themselves adequately effective.

The reasons for the unexpected beneficial effects of the combinedtherapy are not known since the complexity of the pharmacologicaleffects of ibopamine and the complexity of the feed-back mechanismoperating after ACE inhibition do not allow the advance of conclusivehypotheses.

However, the ability of ibopamine of improving perfusion of organs witha dual effect on heart stimulation and vasodilatation allows a betterbalancing of pressure adjustment to the metabolic requirements of theorgans and to the emunctory function of the kidney.

The effects mediated by the DA₂ - dopaminergic receptors on thesympathorenal interactions (reduction of the sympathetic tone andreduction of the secretion of aldosterone and renine) are probably atthe origin of the lack of deterioration of the renal function and of thepreservation of the glomeruli filtration.

For the therapeutical purpose ibopamine or a pharmaceutically acceptableacid addition salt thereof and an ACE-inhibitor are preferablyincorporated in a pharmaceutical dosage form suitable for oral, rectal,parenteral or topical administration.

Depending on the desired administration route, the compositions of thisinvention will be in the form of tablets, capsules, dragees, syrup,drops and the like for oral administration; of suppositories for rectaladministration; of solution, suspensions and emulsions ready forparenteral administration or which are extemporaneously prepared bydiluting a lyophilized preparation; of ointments, creams or medicatedadhesive bendages for topical administration.

Furthermore, for oral administration, slow-release compositions may alsobe used.

Preferred dosage forms according to this invention are the solid formsfor oral administration.

Besides ibopamine or a pharmaceutically acceptable acid addition saltthereof, such as hydrochloride, and an ACE-inhibitor or apharmaceutically acceptable salt thereof, the compositions of thisinvention comprise a carrier or an inert diluent (either solid orliquid) and, optionally, other additives suitable for pharmaceuticaluse, and are prepared according to usual techniques.

The effective dose of ibopamine and of an ACE-inhibitor in thecomposition of this invention will vary depending on various factors,such as the individual response, the age, and the general condition ofthe patient, as well as the intended administration route.

In general, however, the composition of this invention will contain from50 to 100 mg of ibopamine, or the equivalent amount of apharmaceutically acceptable acid addition salt thereof, and from thestandard dose to 1/5 of said standard dose of an ACE-inhibitor or theequivalent amount of a pharmaceutically acceptable salt or of a pro-drugthereof. As used herein the expression "standard dose" means the knownusual dose of said ACE-inhibitor.

Typical examples of preferred ACE-inhibitors according to this inventionare captopril, alacepril, enalapril, lisinapril, cilazapril andramapril.

In general the ACE-inhibitor according to this invention will bepreferably selected from those which are currently administered 2-3times a day in the same manner as ibopamine.

A preferred embodiment of this invention contemplates replacement of theACE-inhibitor drug with a suitable pro-drug thereof.

For example, it has been found that captopril may be helpfully replacedby equimolecular amounts of the S-benzoyl-derivative (described inEuropean Patent No. 0 008 831) or of the S-(methoxybenzoyl)-derivativethereof.

The latter, that is(S,S)-N-(3-(4-methoxybenzoyl-thio)-2-methyl-propionyl)-proline, is noveland is a further object of the present invention.

Its preparation, described in detail in Example 5, is performed byreacting captopril, (S,S)-N-(3-mercapto-2-methyl- propionyl)-proline,with 4-methoxybenzoyl chloride in the presence of a base.

A still further object of this invention is to provide a method fortreating cardiovascular diseases comprising administering to a subjectsuffering from hypertension, heart insufficiency or heart insufficiencyassociated with hypertension a composition containing ibopamine or apharmaceutically acceptable salt thereof and an ACE-inhibitor or apharmaceutically acceptable salt or a pro-drug thereof.

In order to better illustrate the present invention without howeverlimiting it, the following examples are now given.

EXAMPLE 1

    ______________________________________                                        Tablets                                                                       ______________________________________                                        Ibopamine hydrochloride 112 mg                                                (S,S)-N-(3-mercapto-2-methyl-propionyl)-                                                              12.5 mg                                               proline (captopril)                                                           Microcrystalline cellulose                                                                            46.5 mg                                               Polyvinyl-2-pyrrolidone 3 mg                                                  Crospovidone            6 mg                                                  Hydrogenated castor oil 2 mg                                                                          182.0 mg                                              ______________________________________                                    

The active ingredients are weighed accurately and sieved. They are thenmixed together and with a part of the microcrystalline cellulose.

The mixture is granulated with a solution of polyvinyl-2-pyrrolidone,sieved and dried for one night. The remaining cellulose is then added tothe granulate together with crospovidone and hydrogenated castor oil,sieved and then mixed for a few minutes. Finally, the so obtainedgranulate is compressed according to usual techniques.

Working in a similar manner tablets have been prepared containing,instead of captopril, equimolecolar amounts of enalapril and ramipril,respectively.

EXAMPLE 2

Working as in Example 1, tablets are prepared with the followingcomposition:

    ______________________________________                                        Ibopamine hydrochloride 112 mg                                                (S,S)-N-(3-mercapto-2-methyl-propionyl)-                                                              25 mg                                                 proline (captopril)                                                           Microcrystalline cellulose                                                                            50 mg                                                 Polyvinyl-2-pyrrolidone 4 mg                                                  Crospovidone            6 mg                                                  Hydrogenated castor oil 3 mg                                                                          200 mg                                                ______________________________________                                    

EXAMPLE 3

    ______________________________________                                        Film-coated Tablets                                                           ______________________________________                                        A-Tablet Composition:                                                         Ibopamine hydrochloride                                                                              112 mg                                                 (S,S)-N-(3-(4-methoxybenzoylthio)-2-                                                                 20 mg                                                  methyl-propionyl)-proline                                                     Microcrystalline cellulose                                                                           50 mg                                                  Polyvinyl-2-pyrrolidone                                                                              4 mg                                                   Crospovidone           6 mg                                                   Hydrogenated castor oil                                                                              3 mg                                                                          195 mg                                                 B-Coating Composition:                                                        Hydroxy propyl methyl cellulose                                                                      3.3 mg                                                 Polyethylene glycol 6000                                                                             0.7 mg                                                 Titanium dioxide       2 mg                                                                          201.0 mg                                               ______________________________________                                    

The tablets are prepared with a process similar to that of Example 1 andsubsequently coated in a basin with an insulating coating followed by anopaque coating based on titanium dioxide. Coating occurs with an aqueoussolution of hydroxy propyl methyl cellulose and polyethylene glycol inthe proportions indicated above, followed by a second portion of thesame solution, in which the titanium oxide is suspended, according tothe usual film-coating technique.

Working in a similar manner film-coated tablets have been preparedwhich, in place of the S-(4-methoxy-benzoyl) derivative of captopril,contain an equimolecular amount of the S-benzoyl derivative.

EXAMPLE 4

A group of 6 patients suffering from essential hypertension of amoderate degree on a diet with a controlled amount of sodium (100 mEqdie) has been treated for 5 days with ibopamine at a dose of 100 mgthree times a day and then for a further 5 days with three tablets ofExample 2 a day.

The following values of blood pressure (AP) and heart beat (*=p<0.05)have been measured

    ______________________________________                                               Syst. AP   Diastol. AP                                                                             FC                                                       (mmHg)     (mmHg)    (beats/min)                                       ______________________________________                                        Initial  159 ± 5.9 98 ± 3.4*                                                                            75                                             5th day  150 ± 5.8*                                                                             94 ± 2.1*                                                                            77                                            10th day 147 ± 4.7 88 ± 2.4*                                                                            75                                            ______________________________________                                    

EXAMPLE 5 Preparation of(S,S)-N-(3-methoxybenzoyl-thio)-2-methylpropionyl)-proline

To a solution of (S,S)-N-(3-mercapto-2-methyl-propionyl)proline (20 g;0.02 mol) in 0.5N NAOH (184 ml; 0.092 mol are added simultaneously,white keeping the pH at about 9 and temperature at from 0° to 5° C., asolution of 40% (w/v) NAOH (13.8 ml; 0.138 mol and 4-methoxybenzoylchloride (18.8 g; 0.11 mol).

When the addition is over, the said temperature is maintained for 30minutes. The reaction mixture is then made acid with concentrate HCl.After a further 30 minutes under stirring, the solid product iscollected by filtration and crystallized from ethyl acetate. 27 g(Yield, 84%) of(S,S)-N-(3-(4-methoxybenzoyl-thio)-2-methyl-propionyl)-proline are thusobtained, m.p. 140°-141° C.

We claim: 1.(S,S)-N-(3-(4-methoxybenzoylthio)-2-methyl-propionyl)-proline.
 2. Apharmaceutical composition comprising a) the compound of claim 1, b)ibopamine or a pharmaceutically-acceptable salt thereof, and c) apharmaceutically-acceptable carrier; (a) and (b) being present in thecomposition in a combined amount effective for treating cardiovasculardisease, and (b) being present in the composition in an amount effectiveto overcome side effects of (a).